Safety device for electric plugs



Jan; 4, 1949. c. FES'TGE SAFETY DEVICE FOR ELECTRIC PLUGS Filed June 7, 1946 INVENTOR.

HTYOEA/EVS Patented Jan. 4, 1949 UNITED STATES PATENT OFFICE SAFETY DEVICE' FOR EIZECTRIC PLUGS Charles Festge, Milwaukee,.Wis.

Ap lication .Tuh'e'l, 1946,.Serial him-674,946

My present invention relates generally toimprovements in safety equipment and relates more particularly to improvements in the construction and operation of safety devices for electrical accessory plugs.

A primary object of the present invention isto provide an improved device of simple and durable construction adapted to cover the usual current transmitting prongs or metal contact members of electric plugs during insertion thereof in the receiving slots of an ordinary electric outlet or socket switch as well as during removal thereof fromthe outlet. a

It is almost universal practice'toprovide all types" of electrical appliances with an insulated electric conducting cord carrying a plug at the free end thereof, having'a pair of metal contact prongs extending therefrom and adapted to be inserted intore'ceiving slots or sockets of an electric'outlet located on the wall or other convenient place in a building and connected in turn to a source of electrical supply. These plugs are man ufactured of various standard designs and of various insulating materials, but in all of the plugs of this type the metal'contact prongs are spaced a like distance apart. As the prongs of the plug are inserted into the receiving slots of the electric outlet, contact is ordinarily made between the prongs and the current conducting elements of the outlet beforethe prongs have been inserted to their fullest extent. In fact, in many cases, contact is made with the current conducting elements while there is still suiiicient space between the insulated bod of the plug and thewall or face of the outlet or switch box to permit the placing of a finger, particularly a childs, against the bare metal contact prongs; and many accidents have thus been caused, resulting in some instances in severe burns and in other instances even in cleathby electrocution. Furthermore. if only a small space is present between the insul ated plug body and the face of the outlet, there is still a danger of fire if the connection is subjected to-water and danger of serious shock and burns if a person should unwittingly place a hair pin or other metallic object in the space, thereby touching the contact prongs.

It; is therefore an object of this invention to provide an improved device which will eliminate,

or at least minimize, the aforementioned dangers.

Another specific object of my invention is to provide an improved safety device which may be manufactured and sold as a separateappliance adapted for ready application and utilization with 4 Claims. (C1. 173- -361) electri-c'plugs of standard designs, or which may be incorporated as an integral part of the plug.

Another specific object of my present invention is to provide an improved protector cap formed of soft rubber andhaving an integral-skirt adapted toeffectively cover the space between an ordinary electric plug to which the cap may be applied and the face of the wall outlet or switch.

A further specific object of the present invention'is'to provide an improved flexible protector cap which may be readily applied by a novice to an ordinary electric plug as a safety device for reventing accidents.

An additional specific object of this invention to provide an improved safety device for electric plugs which may be manufactured by moldi'n'g or'the like at low cost and which is extremely durable in construction and attractive in appearance.

Still another specific object of my present invention is to provide an improved safety device adapted to be readily applied to electric plugs and having a collapsible depending skirt surrounding the'met'allic contact elements of the plug during actual use.

Ihese and other specific objects and advantages of the invention will be apparent from the following detailed description.

A- clear conception of the features of my present improvement, and of the construction and operation of safety devices built in accordance with my invention, may be had by referring to the drawing accompanying and forming a part of this specification wherein like reference characte'rs designate the same or similar parts in the various views.

Fig. l is a side elevation of a protector cap embodying the invention and adapted for use with one of the: standard types or electric plugs;

Fig. 2 isa top view of the device shown in Fig. l, a portion being broken away;

Fig. 3 is a' longitudinal vertical section through the device'taken on the line 33 of Fig. 2;

Fig 4' is a similar section through the device, showing the same applied to a standard electric plug having its prongs positioned for insertion in the receiving slots of an ordinary electric outlet;

Fig. 5 is a' view similar to Fig. 4 but showing the plug prongs fully inserted in the receiving slots ofthe outlet with the protecting skirt of the: improved device in compressed condition;

7 Fig. 6 is a sideelevatio-n of a somewhat modified protector cap adapted for use with another common type of standard electric plug;

I sarily restrict the scope or utility of the improvement.

Referring to Figs. 1, 2 and 3 of the drawing, the improved safety accessory comprises, in general, a soft rubber body having a. central recess Ii bounded by a side wall l2 and a bottom wall l3, the bottom wall 13 being provided with a pair of spaced slots 14; an integral rib l projecting laterally outwardly from the side wall l2 a relatively thin-walled skirt 16 formed integral with the side wall l2 adjacent the rib l5 and extending downwardly therefrom a substantial distance below the bottom wall [3, the skirt being bowed outwardly away from the wall l2 adjacentthe point of attachment thereto and being bowed inwardly adjacent the free end thereof; and a laterally extending rib l! formed integral with the skirt It at the lower end thereof.

The protecting cap may be readily applied to a standard electric plug l8 as shown. in Fig, 4 by merely slipping the body of the plug l8 into the recess I l with the metallic prongs 19 of the plug extending through the slots It in the bottom wall 13 of the recess ll. When thus applied, the skirt it forms a protecting shield around the contact members I 9, with only a small end portion of the prongs l9 projecting beyond the lower edge of the skirt Hi.

When it is desired to supply energy to the electrical appliance, not shown, by way of the cord 20, the plug l8, having the improved protecting cap applied thereto, is grasped by the hand and the contact prongs I 9 are placed in the slots 2| of the electric wall outlet 22 as shown in Fig. 4. As the prongs l9 are forced into the receiving slots 2|, the flexible skirt I6 of the safety cap seats on the face of the outlet 22 and covers the space between the plug I8 and the outlet face surrounding the prongs IS, the wall of the skirt H5 expanding outwardly, as shown in Fig. 5, as the skirt is compressed. During longitudinal compression and lateral distortion of the skirt IS, the rib I! serves as a reinforcement at the lower edge, preventing the skirt l6 from expanding laterally at the edge and maintaining the skirt edge in contact with the face of the outlet or switch 22; and the rib serves as a limit stop for the skirt I6 during compression thereof and cooperates in maintaining the edge of the skirt in contact with the face of the outlet 22.

While one of the most common types of electric plugs is that having a rectangular cross-section, as illustrated with respect to Figs. 4 and 5, another common type is that having a round crosssection with a spherical cap. In Figs. 6 and :7 a modified type of protector cap embodying my invention and adapted to be utilized with electric plugs of the-latter type is illustrated. Referring to Figs. 6 and 7, the modified safety appliance comprises in general a soft rubber body having a central circular recess 3| bounded by an annular side wall 32 and a bottom wall 33, the bottom wall 33 being provided with a central opening 34 therein; an integral rib 35 projecting laterally outwardly from the annular wall 32; a relatively thin walled annular skirt 36 formed integral with the annular side wall 32 adjacent the rib 35 and extending downwardly therefrom a substantial distance below the partial bottom wall 33, the skirt being bowed outwardly away from the wall 32 adjacent the point of attachment thereto, and being bowed inwardly adjacent the free end thereof; and a laterally extending rib 31 formed integral with the annular skirt 36'at-the lower end thereof.

Obviously, the protecting cap shown in Figs. 6 and 7 may be applied in the same manner as above described with reference to the embodiment shown in Figs. 1, 2 and 3, and the action of this device is precisely the same as abovedescribed with reference to the showing in Figs. 4 and 5. In this modified device, however, it will be noted that instead of the slots I4 of the device of Figs. 1 to 5, inclusive, the bottom wall 33 of the recess is provided with a central opening 34 of sufficient diameter to accommodate both of the contact prongs [9 of an electric plug.

Still another embodiment of my invention is illustrated in Fig. 8 wherein another common type of electric plug is shown as being provided with an integral rubber skirt. The device shown in Fig. 8 comprises in general an'insulated plug 38 carried at the end of a cord 40 and having contact prongs 39 depending therefrom and. surrounded by an annular skirt 46, formed integral with the body 38 and having an outwardly directed rib 41 at the lower edge thereof. In this embodiment the entire plug body and integral safety skirt may be formed of soft rubber, molded to the desired shape, and a limit stop 45 maybe provided as an integral part of the plug body. 38. Obviously, this modified structure functions in precisely the same manner as already described with reference to the other figures of the drawing as a protecting device for covering the metallic contact prongs during use of the electric plug and thereby minimizing the danger of accidents.

From the foregoing, detailed description, it is apparent that my present invention provides an improved protector cap for electric plugs which is simple and durable in construction and which is moreover highly efiicient in actual use. The improved safety device may be readily molded of soft rubber or similar materials to fit the several types of standard plugs now on the market. The improved device may be made in Various colors and is neat and compact in appearance, whether provided as an accessory to standard types of plugs or whether formed as an integral part of the plug. The devices may be assembled by a novice and are effective in minimizing the danger of accidents. In addition to covering the space between the plug body and the wall outlet during insertion of the metallic contact prongs and thereby preventing or at least minimizing danger of shock, the improved device effectively seals the space to minimize the danger of accidents, such as fire, which might be caused by water contacting the metallic prongs.

While the improved safety device has been specifically shown and described herein as comprising a one-piece protector cap formed of soft rubber and having an integral limit stop above the skirt and a reenforcing rib at the free end of the skirt, the device may obviously be modified somewhat to achieve the same results, and in certain instances it may be found unnecessary to provide the limit stop or the reenforcing rib.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the precise mode of use herein shown and described for various modifications within the scope of the appended claims may occur to persons skilled in the art to which this invention pertains.

I claim:

1. An accessory for an electric current conducting plug having contact members projecting therefrom adapted for insertion in a slotted receiving member, said accessory comprising, a body having a permanent pre-formed recess adapted to receive the electric plug, said recess having an apertured bottom wall through which the contact members of said plug are adapted to protrude, and a flexible skirt projecting from said body and extending beyond said apertured Wall.

2. An accessory for an electric current conducting plug having contact members projecting therefrom adapted for insertion in a slotted receiving member, said accessory comprising, a body having a permanent pre-formed recess adapted to receive the electric plug, said recess having an apertured bottom wall through which the contact members of said plug are adapted to protrude, and a flexible skirt projecting from the side of said body adjacent the lower portion thereof and extending beyond said apertured wall, said skirt being of such length as to terminate short of the free ends of said contact members when the accessory is applied to said plug.

3. An accessory for an electric current conducting plug having contact members projecting from one end thereof and adapted for insertion in a slotted receiving member, said accessory comprising, a body having a permanent preformed recess adapted to receive the electric plug, said recess having an apertured bottom wall through which the contact members of said plug are adapted to protrude, and a flexible skirt projecting from said body and extending beyond said apertured wall, said body being freely applicable and removable from the end of the plug from which the contact members project.

4. An accessory for an electric current conducting plug having contact members projecting from one end thereof and adapted for insertion in a slotted receiving member, said accessory comprising, a body having openings adapted to snugily frictionally engage said contact members and being provided with a compressible skirt adapted tosurround the members and to be outwardly distorted when said members are applied to their receiving slots, said skirt when distended being of less length than said members.

CHARLES FESTGE.

REFERENCES CETED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

